| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * (C) 2001 Clemson University and The University of Chicago |
| 4 | * |
| 5 | * See COPYING in top-level directory. |
| 6 | */ |
| 7 | |
| 8 | /* |
| 9 | * Implementation of dentry (directory cache) functions. |
| 10 | */ |
| 11 | |
| 12 | #include "protocol.h" |
| 13 | #include "orangefs-kernel.h" |
| 14 | |
| 15 | /* Returns 1 if dentry can still be trusted, else 0. */ |
| 16 | static int orangefs_revalidate_lookup(struct dentry *dentry) |
| 17 | { |
| 18 | struct dentry *parent_dentry = dget_parent(dentry); |
| 19 | struct inode *parent_inode = parent_dentry->d_inode; |
| 20 | struct orangefs_inode_s *parent = ORANGEFS_I(parent_inode); |
| 21 | struct inode *inode = dentry->d_inode; |
| 22 | struct orangefs_kernel_op_s *new_op; |
| 23 | int ret = 0; |
| 24 | int err = 0; |
| 25 | |
| 26 | gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: attempting lookup.\n", __func__); |
| 27 | |
| 28 | new_op = op_alloc(ORANGEFS_VFS_OP_LOOKUP); |
| 29 | if (!new_op) { |
| 30 | ret = -ENOMEM; |
| 31 | goto out_put_parent; |
| 32 | } |
| 33 | |
| 34 | new_op->upcall.req.lookup.sym_follow = ORANGEFS_LOOKUP_LINK_NO_FOLLOW; |
| 35 | new_op->upcall.req.lookup.parent_refn = parent->refn; |
| 36 | strncpy(new_op->upcall.req.lookup.d_name, |
| 37 | dentry->d_name.name, |
| 38 | ORANGEFS_NAME_MAX - 1); |
| 39 | |
| 40 | gossip_debug(GOSSIP_DCACHE_DEBUG, |
| 41 | "%s:%s:%d interrupt flag [%d]\n", |
| 42 | __FILE__, |
| 43 | __func__, |
| 44 | __LINE__, |
| 45 | get_interruptible_flag(parent_inode)); |
| 46 | |
| 47 | err = service_operation(new_op, "orangefs_lookup", |
| 48 | get_interruptible_flag(parent_inode)); |
| 49 | |
| 50 | /* Positive dentry: reject if error or not the same inode. */ |
| 51 | if (inode) { |
| 52 | if (err) { |
| 53 | gossip_debug(GOSSIP_DCACHE_DEBUG, |
| 54 | "%s:%s:%d lookup failure.\n", |
| 55 | __FILE__, __func__, __LINE__); |
| 56 | goto out_drop; |
| 57 | } |
| 58 | if (!match_handle(new_op->downcall.resp.lookup.refn.khandle, |
| 59 | inode)) { |
| 60 | gossip_debug(GOSSIP_DCACHE_DEBUG, |
| 61 | "%s:%s:%d no match.\n", |
| 62 | __FILE__, __func__, __LINE__); |
| 63 | goto out_drop; |
| 64 | } |
| 65 | |
| 66 | /* Negative dentry: reject if success or error other than ENOENT. */ |
| 67 | } else { |
| 68 | gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: negative dentry.\n", |
| 69 | __func__); |
| 70 | if (!err || err != -ENOENT) { |
| 71 | if (new_op->downcall.status != 0) |
| 72 | gossip_debug(GOSSIP_DCACHE_DEBUG, |
| 73 | "%s:%s:%d lookup failure.\n", |
| 74 | __FILE__, __func__, __LINE__); |
| 75 | goto out_drop; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | orangefs_set_timeout(dentry); |
| 80 | ret = 1; |
| 81 | out_release_op: |
| 82 | op_release(new_op); |
| 83 | out_put_parent: |
| 84 | dput(parent_dentry); |
| 85 | return ret; |
| 86 | out_drop: |
| 87 | gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d revalidate failed\n", |
| 88 | __FILE__, __func__, __LINE__); |
| 89 | goto out_release_op; |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * Verify that dentry is valid. |
| 94 | * |
| 95 | * Should return 1 if dentry can still be trusted, else 0. |
| 96 | */ |
| 97 | static int orangefs_d_revalidate(struct dentry *dentry, unsigned int flags) |
| 98 | { |
| 99 | int ret; |
| 100 | unsigned long time = (unsigned long) dentry->d_fsdata; |
| 101 | |
| 102 | if (time_before(jiffies, time)) |
| 103 | return 1; |
| 104 | |
| 105 | if (flags & LOOKUP_RCU) |
| 106 | return -ECHILD; |
| 107 | |
| 108 | gossip_debug(GOSSIP_DCACHE_DEBUG, "%s: called on dentry %p.\n", |
| 109 | __func__, dentry); |
| 110 | |
| 111 | /* skip root handle lookups. */ |
| 112 | if (dentry->d_inode && is_root_handle(dentry->d_inode)) |
| 113 | return 1; |
| 114 | |
| 115 | /* |
| 116 | * If this passes, the positive dentry still exists or the negative |
| 117 | * dentry still does not exist. |
| 118 | */ |
| 119 | if (!orangefs_revalidate_lookup(dentry)) |
| 120 | return 0; |
| 121 | |
| 122 | /* We do not need to continue with negative dentries. */ |
| 123 | if (!dentry->d_inode) { |
| 124 | gossip_debug(GOSSIP_DCACHE_DEBUG, |
| 125 | "%s: negative dentry or positive dentry and inode valid.\n", |
| 126 | __func__); |
| 127 | return 1; |
| 128 | } |
| 129 | |
| 130 | /* Now we must perform a getattr to validate the inode contents. */ |
| 131 | |
| 132 | ret = orangefs_inode_check_changed(dentry->d_inode); |
| 133 | if (ret < 0) { |
| 134 | gossip_debug(GOSSIP_DCACHE_DEBUG, "%s:%s:%d getattr failure.\n", |
| 135 | __FILE__, __func__, __LINE__); |
| 136 | return 0; |
| 137 | } |
| 138 | return !ret; |
| 139 | } |
| 140 | |
| 141 | const struct dentry_operations orangefs_dentry_operations = { |
| 142 | .d_revalidate = orangefs_d_revalidate, |
| 143 | }; |